Excess body weight is frequently associated with suboptimal endometrial readiness and poorer reproductive success in frozen-thawed embryo transfer (FET) cycles. Administering a depot gonadotropin-releasing hormone agonist (GnRH-a) prior to starting hormone replacement therapy (HRT) has been suggested to enhance endometrial performance through several biological pathways; however, whether this strategy benefits overweight or obese individuals has not been clearly determined. This retrospective analysis included 1968 FET cycles carried out at a major fertility center in Jiangxi Province from January 2016 to December 2021. Overweight/obesity—defined according to Chinese criteria as body mass index ≥ 24.0 kg/m²—was used to identify eligible participants, who were then assigned to either the HRT group (n = 946) or the GnRH-a+HRT group (n = 1022). The study focused primarily on the live birth rate. To limit bias, propensity score matching (1:1) and multivariable logistic regression were applied. Additional subgroup analyses examined outcomes according to lipid-metabolism status.
After matching, 539 cycles per group remained, with baseline variables well balanced. Live birth was more frequent in the GnRH-a+HRT cohort than in the HRT-only cohort (55.84% vs 49.35%, P = 0.033). This pretreatment strategy was also associated with higher rates of positive hCG testing (77.18% vs 68.65%, P = 0.002), clinical pregnancy (68.09% vs 60.48%, P = 0.009), and implantation (52.41% vs 47.47%, P = 0.039). Miscarriage rates did not differ significantly (17.71% vs 16.87%, P = 0.771). Among women with dyslipidemia, the advantage for live birth persisted (adjusted OR 1.75, 95% CI 1.08–2.85), whereas no clear improvement was detectable in those with normal lipid profiles (adjusted OR 1.18, 95% CI 0.87–1.58). These results provide new clinical evidence that GnRH-a pretreatment may enhance FET outcomes in overweight and obese patients, particularly when dyslipidemia is present. An individualized endometrial-preparation approach may therefore be warranted. Larger multicenter randomized trials are required for confirmation.
